Although most can’t be seen by the naked eye, the Earth is surrounded by a spinning field of over 12,000 orbiting satellites. Performing tasks from weather monitoring to beaming the Internet down to rural folks, these complex pieces of scientific equipment make their home up above our atmosphere and only come down once their time is nigh. But therein lies a problem – what is done with a satellite once it has no use? Does it become orbiting space junk, or is it brought back down to Earth?
When re-entering, most of a satellite simply burns up as it scorches through the thickening atmosphere of Earth, but chunky machinery can make it through and reach the surface. If there is a possibility of this happening, the satellite operators must prove that the risk of such an impact causing a casualty is just 1 in 10,000.
Therefore, the best option is to ensure the satellite gets absolutely obliterated before it touches the ground. Manufacturers call this Design for Demise (D4D), an initiative the European Space Agency (ESA) is pushing as part of an effort to minimize space junk.
This is one such demonstration, provided by ESA in partnership with Kongsberg Defence and Aerospace, who are proving that their Solar Array Drive Module (that is, a structural bit of machinery that turns the solar panels to always face the Sun) will never reach the ground should it reenter the atmosphere. In the video below, they use a plasma wind tunnel to simulate the conditions of reentry, and the results speak for themselves.
Watch as the SADM stands absolutely no chance against the plasma onslaught. Credit: European Space Agency
By testing the satellite's heat threshold they can tell if it is likely to survive its fall to Earth before they even send anything up into space. This is one of the few times it's OK to cheer on the side of a plasma wind tunnel annihilating an object in its path.